Air dehydration unit



June 8, 1954 R. s. KOPP 2,680,492

AIR DEHYDRATION UNIT Filed June 22, 1951 REACTIVATING 7 Sheets-Sheet lAT INLET REACTIVA I 'l] 'l HEAT 0U T L; E T

CONDITIONED AIR OUTLET I AIR TO BE CONDITIONED INLET CONDITIONED AIROUTLET 5 35 46 7O 'Hh f! hh E I T F g.2 I: Y {I l l l 5.523%??? k 134ift I :1: I f I I 11% r" 69 i ll 1 J 3nnent0r R. 3 KO PP (Ittorneg June8, 1954 R. s. KOPP 2,680,492

AIR DEHYDRATI ON UNIT Filed June 22, 1951 7 Sheets-Sheet 2 coumnouao AIRou'rLET I6 FI I. 3 4 I I 70 I I I T I 42 I I I I I I I I2 I l 4,3--1'---IIIII I I III J I I I :OIIIJDIIDI'CIDONBEED I'--H I H INLET III II-I I I I I 69 I I I I I l I I I I I 72 LJ L 70 6 CONDITIONED AIR OUTLETFig. 4 I 4 REACTIVATING 42 I To BE R. S. KOPP 6 WQI,

Gttomeg June 8, 1954 R. s. KOPP 2,680,492 AIR DEHYDRATION UNIT FiledJune 22, 1951 7 Sheets-Sheet 3 CONDITIONED AIR OUTLET R E ACT IVATINGHEAT INLET CONDITIONED AIR OUTLET AIR T0 as coNm INLET Zinnentor 36 9RS. KOPP attorney June 8, 1954 R S, KOPP 2,680,492

AIR DEHYDRATI ON UNIT Filed June 22, 1951 '7 Sheets-Sheet 4 CONDITIONEDAIR OUTLET Fly. '7

REACTIVATING- 46/ HEAT INLET 60 CONDITIONED AIR OUTLET 3nventor R. S.KOPP Gttorneg June 8, 1954 R. s. KOPP 2,680,492 AIR DEHYDRATION UNITFiled June 22, 1951 7 Sheets-$heet 5 3nnentor R. 's. KOP P (IttornegJune 8, 1954 R. s. KOPP 2,680,492

AIR DEHYDRATION UNIT Filed June 22, 1951 7 Sheets-Sheet 6 "Fig. IO

3maentor R. S. KOPP attorney June 8, 1954 R. s. KOPP AIR DEHYDRATIONUNIT 7 Sheets-Sheet 7 Filed June 22, 1951 Zhwentor R. S. K O P P Q2attorney Patented June 8, 1954 UNITED STATES PATENT OFFICE 2,680,492 AIRDEHYDRATION UNIT Roger S. Kopp, Arlington, Va. Application June 22,1951, Serial No. 232,990 Claims. (01. 183-4.6) This invention relates toair conditioning units A still further object of the invention is toproof the type adapted to be used in air conditioning vide an improvedmethod of air conditioning and cooling systems of rooms, buildings, andthe which comprises causing the air to be treated to like for thepurpose of maintaining relative huflow in contact with a compressedfibrous matemidity of any desired degree therein. rial having ahygroscopic salt uniformly distrib- An object of the invention is toprovide an imuted therethrough, successively exposing dry composedabsorption plates, wh ch wheel 1s so aiabsorption of mo1sture by thematerial and subranged within a casing that the air to be COIldI- Inquently exposing the wet material for contact tioned flows through thewheel in such a man with heated air having a predetermined temperherthat the moisture in the air is absorbed by e in a y g C a r w y h m tia the heel, is dried a predetermined amount so that a con- Anotherobject of the invention is to provide an stant relative humidity of anydesired degree can improved air conditioning unit comprising a bemaintain d in the treated air by the degrees wheel rotatable solely bygravity and composed of proportionate temperature u e n the drying of aplurality of radially disposed absorption hambe plates, and having acasing enclosing the wheel Wi h the foregoing and other objects andadand formed with a. series of plenum chambers so vantages in view, theinvention consists in the flows through th h 1 only my a dlrectmnbseveral parts which will be hereinafter more fully stantially parallelto the axis of rotation of the described and claimed. wheel. In theaccompanying drawings:

Another object of the invention is to provide Fig. 1 is a top plan Viewof on ir'o d an improved air conditioning unit comprising unit embodyingthe Present ve t n; means for causing the 'air to fiow in contact with 2is an elevation of e unit Shown in an absorption material adapted toabsorb moislooking at the reaotivatihg eat inlet side I ture from theair, means for exposing the wet thereof;

material for contact with heated air having a pre- 3 is an elevationlooking at he e pp site to the side shown in Fig. 2;

Fig. 4 is an elevation looking at the rear of the sequently exposing thedried material to the air unit;

to be conditioned whereby a, constant relative f' 5 is an elevation ngat he front of the humidity of any desired degree can be maintained fi gi i in the treated air by the degrees of proportionate a 6 is a verticalsection en along he line temperature used in drying the wet material ofAnother Object of the invention is to provide an Fig. 7 is a verticalsection taken along the line improved air conditioning unit comprisingmeans of 6; for causing th air t flow in t t t an Fig. 8 is a verticalsection taken along the line absorption material adapted to convertthelatent of heat of the air into sensible heat and to increase 9 is aVertical Section taken along the l ne the sensible temperature of theair proportional of to the quantity of moisture absorbed, and means 10is n nlar ed section of the hub of the for reducing the sensibletemperature of the de- Wheel taken along the line l9|0 f 6; humidifiedair. Fig. 11 is an enlarged section of the rim of the Another object ofthe invention is to provide Wheel taken along the line l of and animproved method of dehumidifying air which 121's an enlarged Section othe hub porti n comprises causing the air to flow in contact with of theWheel Shown in a compressed fibrous material having a hygro- Referring tthe d w s, and especially to scopic salt uniformly distributedtherethrough, Fig. 6, the improved air conditioning unit comabsorptionof moisture by the material, and subfully described. sequently exposingthe wet material for contact The wheel H has a shaft l3 of suitablelength, with heated air to remove the moisture therefrom. and a bearingI4 is mounted on the shaft near each end thereof so that the shaft andthe wheel thereon are free to rotate in the manner to be hereinafterreferred to. Each bearing [4 is supported by a standard i5, as shownbest in Figs.

6 and 12.

The wheel i i has a pair of spaced hubs i6 fixed to the shaft I3 bymeans of set screws or other suitable fastening means, indicated at M,Fig. 12. Each hub is formed with a plurality of radial bores i8 whichextend inwardly from the outer periphery of the hu the inner portion ofeach bore it being formed with screw threads iii.

A rod 20, having an inner end threaded portion 2|, is mounted in eachbore it, the screw threads of the portion 2i of the rod engaging thescrew threads is of the bore 18 so that the rod is tightly secured tothe hub I6.

In the present instance, each hub 1'8 is shown as being provided withsix rods 28. understood, however, that any suitable number of rods 2%may be employed, depending upon the size of the wheel and otherstructural character istics which might enter into the design andconstruction of the invention.

Encirclingthe outer ends of the rods 28 carried by each hub it, is anannular band 22 which is secured to each rod bymeans of a screw or othersuitable fastening element, as indicated at 23, Fig. 11'. Each band 22is located in substantially the sameplane as is each hub I5 of thewheel,

and said bands constitute the rims or fellies of the wheel, as shown inFig. 6. The rods are the spokes of the wheel.

Disposed between the hubs l6 and the rims or bands 22, is a plurality ofplates 25. These plates 25are preferably formed from rectangular sheetsof suitable material, and all of said plates should preferably beefequal size and weight, so that when the plates are assembled in thewheel, the

wheel will be balanced and free to turn on its axis. In order to providemeans for retaining the plates 25 in position an inner retainer 25 isfastened to the hubs lt'yand an outer retainer 2'1 is fastened to eachband or rim 22.

As shown in Fig. 10, the inner retainer 26 may be in the forrnof a tubeof corrugated sheet metal, which tube encircles the hubs 1 S andenclosesthe portion of the shaft i3 between said hubs. (see alsoFigs. 6and 12.). This tube with the corrugations formed lengthwise. thereof,providesa series of radiall-y disposed slotsor grooves 28, into each ofwhich is inserted an edge portion of a plate 25-.

In order-toprevent shiftingmovement of the plates lengthwise of theretainer 25, a plate 29- is mounted on the outer face of each hub 15.The

plate 29 is formed with a central opening 30 some what larger indiameter than the diameter of the shaft it, so that when it is desiredto remove or insert a plate'ib, the plate29 can be detached from the hubi5 and then shifted to dispose the outer periphery thereof inwardly withrespect to the outer periphery of the hub IS. The plates 25 may bedetachably secured to the hubs it by screws or. other suitable fasteningmeans, as indicated at 3|, Fig. 12.

As shown in Fig. 11, the outer retainer 2'! may be in the form of astrip of corrugated sheet metal which is secured in any suitable mannerto the inner face of each band 22. The metal strips 2'! provide a seriesof slots or grooves 32 into each of which is inserted an edge portion ofa plate 25.

Since the plates 25 are arranged radially of the wheel, the grooves 28are disposed close together, andthe grooves 32 are disposed somewhatfarther. apartwith respectto the spacing of the It Will be.

the submerged plates to-become grooves 28. In actual practice the wheelsI i have been constructed with approximately plates. In this way theplates were spaced apart an angle of approximately 2 degrees.

In Fig. 9 a typical arrangement of the plates 25 between two of thespokes or rods as has been shown. It will be understood that in bothFig. 9 and Fig. 10, the plates extend entirely around the hub of thewheel, said plates being uniformly spaced apart.

The plates 25 are preferably formed of inert, fibrous, light-weightmaterial'with a high factor of absorption. One material suitable for usein constructing. the plates is rock wool, or as is commonly Known,asbestos, since such material can be molded or formed into boards orsheets of different thicknesses, and it is also adapted to variousdegrees of density and rigidity which, in consequence, permits its useover such a range as to meet the conditions which may be imposed upon itby differences in mechanical design.

In addition 'to asbestos fibres, other suitable materials for the baseof the-plates 25 are balsam wool, kapok, eel grass, rock cork, sugarcane fibre, cotton linters, wood pulp and the like textile fibres, and,in fact, any otherknown inert fibrous material.

Since the plates 25 should be treated so as to render them highlyabsorbent to moisture in air flowing through the unit,.any method may beused to prepare the inert fibrous materials foruseas dehydratingmaterials. 7

By one method I have used wool or asbestos boards or sheets as producedby manufacturers of asbestos products. These sheets are saturated in asolution of hygroscopic salt, such as calcium chloride (CaClz), or anyother hygroscopic salt. In some cases compounds ofseveral of thehygroscopic salts have been used.

In order to properly saturate the plates 25, the latter are submerged ina salt solution until the fibres of the plates are thoroughly wet.Usually it-requires approximately one hour for urated. Of course,theamount plates should be submerged in the salt solution depends uponthekind of material and the density thereof, but ordinarily after theplates have been submerged in the salt solution for anhour they. arethoroughly saturated; plates are then dried to remove therefronn. Indrying the plates, they may be placed. in a continuousdryer under acounter flow ofair heated to a temperature of 180 F. to 220 F. Usuallythe plates must remainin the dryer for approximately one hour before themoisture is entirely removed therefrom. When the plates. are. thusprepared, the hygroscopic salt or salts will. be evenly distributedthroughout the inert basematerialin fixation inits dry state.

In addition to calcium chloride referred to above, lithium chloride(IiCl) lithium bromide (LiBr), calcium bromide (CaBrz), and otherhygroscopic salts-having in their normal state low vapor pressures mayalso be used for treating the plates for use in the apparatus of thepresent invention.

When exposed to air or gases having a higher vapor pressure than thehygroscopic salt; the salt absorbs vapor saturation occurs. Namely,saturation occurs when the vapor pressureof. the

the standard rock thoroughly sat-.

.of ,time the The saturated the moisture from the air or gases untilhygroscopic solution is raised by absorbing so much-moisture andrectionparallel to the shaft I3.

diluting the hygroscopic solution to that point where absorption ceasesand equilibrium occurs.

The upper portion of the and 3B are arranged close to the outerperiphery of the wheel I l, the clearance between said walls and thewheel being sufficient to permit free rotation of the wheel.

Since the walls 35 and 36 enclose the periphery of the wheel II,chambers are formed in the casing l2 at each Each end of the wheel H isspaced a suitable distance from the end At the front of the the At therear of the device and located between and the rear wall 42, there is atubular member 44.

The ends of the tubes 43 The front tending peripheral flange 45 whichoverlaps the laps the rear edge of the wall 35.

The front end portion of the device is pro- If so desired, an L-shapedwall the walls 41 and 48.

. The rear end portion of the device is provided with four partitions orwalls GI, 62, 63 and 64 may connect which extend flange 4'6 and aplurality of 68. The chamber 65 is connected to an air to be conditionedinlet by flanged openings 89, I0, manner.

The air to be conditioned entering the chamber 65 through the inlet 69passes chamber 57 substantially between the top and bottom of thechamber, as shown in Fig. 8.

From the upper portion of the chamber 5'! the The radiator 16 has aninlet connection 19 and an outlet connection 80. The direction in whichthe cooling fluid flows through said radiator is indicated by arrows inFig. 7.

The purpose of the radiator 36 is identical with the purpose of radiator15, but the radiator 76 in consequence a greater pressure becomessorption of moisture by the The plates 25 difference of vapor plates. ofthe wheel will absorb up to rotate (see my Patent No. 2,115,226). in thesection of the wheel between .51 and 65 are The plates chambers wetterthan the plates between available for more efiicient abaes roazthe-chambers 51: and 166:, chambers 58 and .66' are and the platesbetween drier. than the: plates: of

the. wheel disposed .betweencharnbers 51. and .66..

Thecounterflow of air through the: wheelabovereferred .to' is;important. The plates between 61 being. wetter,.have a higher the air,making its first pas.-

therefore, permits the moist plates of the wheel toabsorb quantities ofmoisture 1 from .the: moistair.-

The second passageof air through the-wheel is of that air which has beenpartially dried, and this drying process will reduce the vapor pressureof the air, butthe section of the wheel disposed between chambers 51 andfifiwhich is comprised of drier plates, also because of its relativelygreater lower vapor pressure, will extract additional moisture from thepractically dry air which has passed through the wheel between chambers65 and 51.

The heated reactivating air enters the separate plenum chamber 51;: Fig..7, and flows through the wheel in the same manner as the air to be:conditioned flows through the wheel into chamber 59, Fig.8, andcounterflows through the wheel and into chamber 68, Fig. 7, from whichitis exhausted through the outlet 12, Fig. 4. This passage of heated airthrough the wettest part of the wheel dries the moisture from theplates, thereby permitting the wheel to turn in its normal cycle as itaccumulates more moisture from the air being conditionedin the mannerabove referred to.

It should be noted that the plates 25 of the wheel I! which are disposedbetween the chambers. 5S. and ii!- are drier than the plates disposedbetween the chambers 59 and 68.

The temperature of the air supplied to the re activating heat inlet I'lwhichis used to dry the plates of the wheel. ll need not exceed 150 F.under normal operating conditions. The entering reactivating heated airin passing over the drier section of the wheel, first picks up aquantity of moisture, and in so doing, the sensible heat of the drying.air is reduced. This-iscaused by the absorption of moisture by thedrying air. This sensible temperature of the then. further reduced asthe air absorbs more moisture from the wetter plates in its second pas-I sage through the wheel between chambers 59 and 68. Consequently,effective drying is obtained: at relatively low temperatures, which inturn permits accurate control through the heat exchange that occurs onthe adiabatic line, as all drying temperatures are within this definiterange.

This adiabatic range also' permits application of the quantity andvolume of heat so that any degree of dryness of the plates within basicchemical limits maybe appliedwhich in turn is the through which anydesired vapor pressure means difierence within chemical limits can beobtained through which the ante be conditioned is subjected.

From the foregoing it'will be noted that I have provided a new method ofdehumidiiying air which comprises passing the air in contact with acompressed fibrous. material having a hygro-.

scopic salt uniformly distributed therethrcugh. This action converts thelatent'heator the air into sensibleheat and consequently increases thesensible temperature of. the-air in proportion to the wheel disposed.

heated: air is through the radiators 15 the quantity: of.moistureabsorbed. Since the wheel I I becomes overbalancedasitcollectsmoisture in the section thereof defined by the. plenum chambers 51.. and65,.the wheel slowly rotates so that iresh material is. successivelyexposed :for contact with the air at the rate of absorptionof moisture;The method further includes reducing ture of the air by passing the airsuccessively and 15. Finally,- the wet absorption material of thewheelis exposed for contact with the heated air'admitted' through theinlet ll, and thus. the moisture is-removed therefrom before thisportion of the wheel moves into alignment with. the upper plenum chamber58.

The laws governing water vapor absorption from. air by calcium chloride.solutions have-been determined in experimental and full-size units. Itisfound that the amount of water absorbedin unit. time on unit area ofabsorbent is directly proportionalto the difference in vapor pressureofwater in the air and in the absorbing solution, and. to the 0.8 powerof the velocity of the-air past that area.

Thisrelationship isexpressed thus:

=0.030l pW- -Agms/hn. ==O.462 pl! A grains/hr.

where For a velocity or 100045. RM; over the absorb-. ing surface, V-=approximately 252. and

10:7.59' p A gins/hr. =117 1) A grains/hr.

This;

formula. agreesaccurately with those which. can be. calculated from heattransfer-coefficients and. the relationbetween heat transfer and watervapor difiusion. They are independent of temperature.

The same. formula in reverse applies onthe drying. side.- .ofthe wheel.

Without the application of heat to the drying side. the wheel will turnandthe plates absorb until the wheel attains equilibrium. However,- whendrying is started or occurs on thereacti vating side: of the wheel,the-moisture deleted thereby provides absorption capacity equal to theamount dried. The more completely the plates are. dried in reactivation,the greater is the amount which they can absorb on the conditionineside-In like manner the lower the temperature of the. drying air the morewater or moisture is left in the plates and the lower is theability ofthe plates to absorb. It is accurately proportional and equal to themean temperature difference.

The wheel permits motion only ifsufficient absorption occurs toover-balance it. The rate at whichthe wheel rotates about its axis andthecapacity of the wheel within the formula is the direct reciprocal ofthe drying: of the plates. For

thesereasonsthe device can maintaina constanta rate. proportional to-.thesensible temperaof radially disposed flat absaid absorption platesbeing uniapart whereby the wheel is norsorption plates, formly spacedchambers formed in the casing at each end of said wheel, means forconducting moist air into said plenum chambers axially through a segmentof said wheel to permit absorption of moisture by the plates then insaid segment, and means for conducting heated ing with the loss ofmoisture by the plates in the angularly offset segment of the wheel tounbalance and effect rotation of the wheel.

4. Apparatus according to claim 3, including cooling means associatedwith said casing in the path of the moist air being conditioned.

5. An air conditioning unit comprising a wheel including a plurality ofradially disposed flat absorption plates, said absorption plates beinguniformly spaced apart whereby the w .eel is normally balanced, meansfor supporting said wheel casing and by means of said plenum chambersaxially through a segment of said wheel to permit absorption of moistureby the plates then in said segment, and means for conducting heated airinto said casing and by means of other plenum chambers axially throughan angularly offset segment of said wheel in a plurality of successiveback and forth passes to permit absorption of of the wheel opermoistureby the plates in the angularly offset segment of the wheel to unbalanceand effect rotation of the wheel.

6. An air conditioning unit comprising a wheel including a, plurality ofwheel, means for conducting moist air into said casing and by means ofsaid plenum chambers axially through forth passes to permit absorptionof moisture by said heated air from the plates then in said oiisetsegment, the absorption of moisture by the plates in one segment of thewheel operating with the rotation of the wheel.

7. An air conditioning unit comprising a wheel including a plurality ofradially disposed flat absorption plates, said absorption plates beinguniincluding plural coohng means associated with said casing in the pathof the moist air being conditioned to cool said air between successivepasses through the wheel.

9. An air conditioning unit comprising a wheel including a plurality ofradially disposed flat ab sorption plates, said absorption plates beinguniformly spaced apart whereby the wheel is normally balanced, means forsupporting said wheel for free rotation about a horizontal axis, acasing enclosing said wheel, a plurality of plenum chambers formed inthe casing at each end of said wheel, means for conducting moist airinto said axially through a segment of said wheel to permit absorptionof moisture by the plates then in said segment, means for conductingheated air into one side of said casing and by means of other plenumchambers axially through an angularly oiTset segment of said wheel insuccessive back and forth passesto-permit absorption of moisture by saidheated air fromthe-plates then .in said offset segment, the'final heatedair pass :being through alower portion oisaid ofiset segment and belowthe first heated air pass, and an outlet for conducting heated airout ofsaid casingtadjae cent the bottom thereof, the absorption'of moisture-by the plates in one segmentofxthe wheel operating with the loss ofmoisture bytheplates in the. angularly off-set segment of the wheel tounbalance and effect-rotation ofthewheelr 10.- An air conditioning unitcomprising. a wheel including a plurality of radiallydisposed flatabsorption plates, said-absorption plates beinguniformlyspaoedapart'whereby the wheel is normally-balanced, meansforsupporting said wheel for free rotation about a horizontalaxiaacasing enclosing said wheel, aplurality of plenum .chambers formed inthe-easing ateach end oijsaid wheel-,- means for conducting moistairyinto-zone side of said casing adj'acent the ebottomthereof and,.by-: means of said plenumcham-bers :axiallythrough a segment of saidwhee in three succes sive back and forth passes to permit absorption ofmoisture. by theplates then in said-: segment; each successive passbeing through a higher portion ofsaid segment, anoutlet for conductingconditioned-air out'of the oppositeside of said.

casingadjacent ,the .top thereof, meansefor scondueting heated air into.one side: of said casing and by means of other plenum: :chambers axiallythrough an angnlarly offset segment oi said wheel in successive backand; forth passes to permit-absorption: of moisture by said heated airfrom the plates then in said offset segment, the final heated air,passbeing through a lower portion ofsaid offsetsegment and below thefirst heated air pass,- andaan outlet for conducting heated air out ofsaid casingtadjacent the bottomtthereof, the absorption ofmoistu-re bythe-platesr-in one-segment of the wheel operating with the loss ofmoisture by the platesin, the angularly offsetsegment of the a wheel to1 unbalance and .efiect rotation :of-the wheel.

Referenees, Cited in. .thenfileiof this. patent UNITED. STATES PATENTS.

